2D matrix with Flyweight Design Pattern

I produce 2 square matrices A and B both of size 8192x8192 filled with complex numbers. I want to calculate the Discrete Fourier Transform of A+B. But it’s not as simple as that. I have access to multiple cores and I can do parallelize for this process. But I can't create 2 square matrices A and B both of size 8192x8192 because of java.lang.OutOfMemoryError. How can to handle with Flyweight design pattern and threads? How can i solve this solution? I couldn't find a way out to enlarge memory.